Compressing member



Sept. 11, 1962 M. L. KLINGLER COMPRESSING MEMBER Filed June 14, 1960 2Sheets-Sheet 1 Q Z U 2 5 6 REM ID 5 TIME TT INVENTOR.

mHRHN L. KLINGLER p 1962 M. L. KLINGLER 3,053,112

COMPRESSING MEMBER Filed June 14, 1960 2 Sheets-Sheet 2 4% INVENTOR.

mam LKUNGLER a! hilly v 3 T BY M MQMM United States atent 3,053,112COMPRESSING MEMBER Martin L. Klingler, Hershey, Pa., assignor to AMPIncorporated, Harrisburg, Pa. Filed June 14, 1960, Ser. No. 36,023 9Claims. ((11. 74585) This invention relates to compressing tools,particularly of the type adapted for metal working operations such asterminal crimping, rivet setting, bending, and forging. The invention isherein disclosed in an embodiment of a terminal crimping tool, however,it will be apparent that the invention is not limited to this particulartype of operation.

Several design and performance requirements of tools of the class towhich the instant invention pertains should be appreciated for a fullunderstanding of the objects of the instant invention. In general,compressing tools are employed to perform metal forming operations inwhich the force required increases as the stroke of the ram proceeds andreaches a maximum level at or near the end of the stroke. It is alsodesirable in such tools that the compressing dies (cg. the crimping diesin the case of a terminal crimping tool) be capable of opening or movingapart a substantial distance in order to permit the work piece to bepositioned therebetween. Thus, when a tool of this type is actuated, theram may travel a substantial distance during which it encounters verylittle re.- sistance and during which it need not therefore develop muchthrust. During the final portion of the stroke of the ram, however, theresistance increases abruptly and may reach a substantial level. Duringthis final relatively small portion of the stroke, most of the workwhich is done during the cycle is accomplished. By way of example, thecase of a typical terminal crimping tool can be cited in which a dieopening of one-half inch is required to permit positioning of theterminals between the dies. The design of the terminals, however, issuch that the actual crimping operation-requires only about 0.1 inch'ofram travel and during the very last portion of this 0.1 inch of travel,the force developed may go as high as 4000 pounds. It will be apparentupon reflection that similar conditions exist in, for example, rivetsetting operations since the resistanceto deformation increases as therivet is deformed and the final portion of the stroke of the rivetingdie requires a much greater applied force than the initial portion ofthe stroke. It should be added that a desideratum of these tools isusually small size since the work pieces, for example, terminals orrivets, are usually very small and it is advantageous to have a toolwhich can be manually held and transported easily to the site of theworking operation.

It will be apparent from the foregoing discussion that it would beimpractical to mount the ram of a compressing tool directly on afluid-actuated piston for the reason that a relatively large diameterpiston having a long stroke would be required to accomplish a large dieopening and furthermore, much of this stroke would be wasted since themaximum force is developed only during the very final stages of thestroke of the ram. Many of the presently available compressing toolstherefore provide a force multiplying means between the piston and theram to achieve a quick take-up during the first portion of the stroke ofthe piston (i.e. a substantial movement of the ram during the first partof the stroke of the piston) followed by a compressing, or metalworking, portion of the stroke during which the piston may move asubstantial distance and the ram will move only a relatively shortdistance but will develop a relatively high thrust. Force multiplyingdevices of this type have, in the past, quite frequently been providedin the form of a simple slidable cam which engages the ram directly ormay engage some intermediate linkage which in turn causes the ram tomove. While tools of this type are widely accepted and have provedhighly successful, they suffer from the disadvantage of developingrelatively high frictional forces, particularly during the final portionof the stroke of the cam. Since the ram thrust reaches very high levelsduring this final portion of the stroke, the linkage extending from theram tothe piston is also very highly stressed and where the cam orsimilar device must slide over a bearing surface, very high frictionalforces are developed which tend to detract from the useful force andwork available on the end of the ram. In many tools, roller bearingshave been employed to reduce the frictional forces developed but sucharrangements render the tools more expensive to manufacture andundesirably complex.

It is accordingly an object of the present invention to provide animproved tool which obviates, or.reduces the effect of, the foregoingproblems associated with compressing tools. A further object is toprovide a compresssing tool having an improved force multiplying linkagebetween a power source, such as a piston, and a compressing ram. Afurther object is to provide a tool which is simple in construction andwhich reduces the effects of friction during the power stroke. A stillfurther object is to provide a fluid-actuated tool in which a smallportion of the stroke of the piston is utilized to move the ram asubstantial distance leaving a major portion of the stroke of the pistonto accomplish the work required of the ram during the stroke. A stillfurther object is to provide a tool having means to ensure that, inevery cycle of operation, the ram will travel a predetermined distanceto perform a specific operation (such as terminal crimping) before theram is permitted to return to its starting position.

These and other objects of the invention are achieved in one preferredembodiment comprising a cylinder having a piston therein at one end andhaving a ram extending from its opposite end. The ram is pivotallyconnected to one end of a toggle, the opposite end of which is mountedon a fixed pivotal axis. This toggle is normally broken and its kneejoint is normally in engagement with the face of a block which in turnhas a pivotal connection with the piston. The block, which functions asboth the pushing block and a camming block, is mounted by means ofparallel links for movement along an armate path so that as the pistonmoves from its normally retracted position, it first pushes the kneejoint of the toggle to substantially, but not fully, straighten thetoggle links and to achieve a relatively large displacement of the ram.Thereafter the knee joint of the ram contacts a camming surface on theblock and during the remainder of the stroke of the piston this cammingsurface further straightens out the toggle and drives the ram to thelimit of its travel. The camming surface of the block is so contouredthat it compensates for the arcuate path along which the block itselfmoves during the stroke.

In the drawing:

FIGURE 1 is a perspective view of a tool in accordance with theinvention. 7

FIGURE 2 is a sectional view of the interior of the cylinder of the toolshown in FIGURE '1 and showing the positions of the parts at thebeginning of the operating cycle. I

FIGURES 3 and 4 are views similar to FIGURE 2 but showing the relativepositions of the parts at an intermediate stage and at the final stageof the operating cycle.

FIGURE 5 is a view taken along the line 5--5 of FIGURE 2.

. FIGURE 6 is a perspective view of the camming block which forms partof the invention.

FIGURE 7 is a view taken along the lines 77 of FIGURE 5.

FIGURE 8 is a view taken along the line 88 of FIGURE 7, and

FIGURE 9 is a graph illustrating the movement of some of the partsduring th stroke of the tool.

The disclosed embodiment of the invention, a crimping tool for crimpingelectrical terminals onto the ends of wires, comprises a cylinder 2which is adapted to be manually held and which is closed at its upperend by a cylinder head 4 through which the end of a ram 6 extends.Mounted on the upper portion of the tool, by means of ears 8 integralwith the cylinder head, is a generally C-shaped tool head 10 having adie holder 11 secured thereto in which upper or fixed crimping dies 16are mounted. Complementary lower crimping dies 12 are mounted on a dieholder 14 which, in turn, is secured to the upper end of the ram, thisstructure not being shown in FIGURES 24 in the interest of simplicity.In use, a terminal is merely positioned on the lower dies and the toolis actuated to drive these dies into engagement with the upper die 16 tocrimp the terminal. In the disclosed tool, as in similar types ofmetal-forming tools, a large die opening is desirable to permitpositioning of the work piece between the dies. The present inventionconcerns the actuating means for the ram 6 and will now be described.

A reciprocable piston 18 is mounted in the lower portion of the cylinder2, as viewed in FIGURE 2, and a conduit 20 supplies motive fluid to thelower end of the cylinder to drive the piston upwardly. Advantageously,a lever 22 is provided on the exterior of th cylinder for controllingthe valve (not shown) by means of which the motive fluid is admitted to,and exhausted from, the cylinder. Piston 18 is normally biaseddownwardly, as viewed in the drawing, by means of a spring 25 interposedbetween the face of the piston and a plate 24 which divides the interiorof the cylinder into an upper portion, in which the force multiplyinglinkage is mounted, and a lower portion in which the pistonreciprocates. A piston rod 26 is pivotally secured at one end to thepiston and has its opposite end received within a slot 27 in a block 28and is pivotally secured to the block at 29. It will be noted that thelower end of this block, again as viewed in FIGURE 2, projects throughan opening in the plate 24 while the upper end thereof is receivedentirely within the upper portion of the cylinder. A generally U-shapedhousing integral with the cylinder head 4 has a web portion 30conforming to the curvature of the interior of the cylinder wall and hasa pair of parallel side walls 32 projecting towards the center of thecylinder. As best shown in FIGURE 5, block 28 is in alignment with thishousing so that the central body portion 34 of the block extends betweenthe side walls while the portion 36, which is enlarged, extendslaterally so that its sides are coplanar with the external surfaces ofthe sidewalls 32. Block 28 is mounted within the cylinder by means oftwo pairs of parallel links 38, one pair being provided on each side ofthe block and each end of each link being pivotally secured at 42 to theblock and at to the side walls 32.

The lower end of ram 6 is provided with a threaded adapter 43 which hasa lower end pivotally connected to a toggle mechanism generallyindicated at 46, and 48. As is apparent from FIGURE 5, this togglemechanism comprises two links 46 and two links 48, the links 46 beingmounted on a pin 44, which extends through the ram adapter and throughthe side Walls 32 of the housing as indicated in FIGURES 7 and 8. Thelower links 48 of the toggle are received on the lower most one of thepins 40 so that a common pivotal axis is provided for the lower set oflinks 38 on each side of the block and the lower links 48 of the toggle.The knee joint 52 of the toggle (the common pivotal axis for the links46, 48) has a roller 54 in surrounding relationship thereto engageablewith the block 28 as described below. The toggle joint is normallybiased to the position of FIGURE 2 by means of springs 56 (FIGURES 7 and8) on each side of the side walls 32 which surround rods '58 extendingfrom the plate 24 to the cylinder head. The right-hand ends of thesprings as viewed in FIGURE 8 are connected by means of rods 60 to theend portions of the pin 44 which extend through elongated slots in theside walls 32. This arrangement permits upward movement of the ram andstraightening of the toggle as viewed in FIGURE 2 but normally biasesthe ram and toggle to the position of FIG- URE 2. Advantageously a leafspring 64 is mounted in the housing having an outwardly bent end portion62 which tends to break the toggle when the parts are in the positionsof FIGURE 4. This arrangement causes the toggle to be automaticallybroken so that the ram can be pulled downwardly by the spring 60 whenthe block 28 is in its lower position. A set screw 61 is provided inhousing 30 to act as a stop for the knee joint as viewed in FIGURE 4.

The block 28 has an inclined leading face 66, which is engageable withroller 52, and a cam surface 68 which is also engageable with theroller. When the block and piston are in their retracted positions asshown in FIG- URE 2, the roller bears against the face 66. Upon upwardmovement of the block and piston, the roller and knee joint of thetoggle are pushed causing the toggle to be substantially, but not fully,straightened out until the position of the parts of FIGURE 3 areachieved. Thereafter the roller engages the contoured cam surface 68 sothat upon further upward movement of the block the toggle is furtherstraightened out and the ram driven upwardly. It will be noted that thesurface 68 is contoured to compensate for the fact that the block 28moves along an arcuate, rather than a straight-line, path during thestroke of the tool.

In some operations, for example in crimping terminals, it is desirableto provide means to assure that, once a cycle is initiated, the partswill go through a predetermined series of motions and the ram willtravel a predetermined distance before the parts can return to theirstarting positions. In the disclosed embodiment there is provided in theslot 27 a spring biased pawl 70 having an end portion which extendsbeyond the block and into a recess 74 in a bar 75. This bar is slidablyheld between the face of the cylinder head 4 and the surface of theplate 24 so that it can move rightwardly and leftwardly as viewed inFIGURE 2 although it is not permitted axial motion. Ratchet teeth 72 onan intermediate portion of the bar are engaged by the pawl during upwardmovement of the block and prevent return motion of the parts until thepawl enters the uppermost notch 76 in the bar which permitsreorientation of the pawl and downward movement of the block. It will beapparent from FIGURE 5 that the bar itself is held in place by means ofa channel 78 movable with respect to the bar and secured by means offasteners on the lower surface of the block as viewed in FIGURE 5.

The movements of the parts during the operating cycle have beenexplained above and are apparent from FIG- URES 2-4. As the ram movesupwardly, during a relatively small portion of the stroke of the piston,the knee joint 54 is pushed (rather than cammed) and moves rightwardly.This initial movement of the piston results in substantial travel of theram because of the nature of the toggle linkage between the block andthe ram. After the roller 54 has encountered the cam surface 68 of theblock the roller is cammed rightwardly and during this intervalrelatively high pressures or unit stresses can be developed thereby toimpart relatively high thrust to the end of the ram for the crimping orother operation. The relationships are shown in the graphs of FIGURE 9wherein it can be seen that the ram travels a substantial distanceduring the very first portion of the travel of the piston, and then, theram travels the remaining relatively small portion of its stroke whilethe piston travels a relatively long distance which remains for itsstroke. The effect of this arrangement is that the work available by thetravel of the piston is substantially all usefully employed in thecrimping operation and is not wasted in merely driving the ram upwardlyagainst substantially zero resistance.

It will be noted that the surface 66 of block 28 slopes downwardly andaway from the toggle as viewed in FIGURE 2. This feature of disclosedembodiment provides the extremely quick take-up described above andfurther illustrates the fact that during initial upward movement of theblock, the knee joint is not cammed rightwardly, in the usual sense, butis pushed and moves rightwardly of its own accord. It will be apparentthat the ratio of ram movement to piston movement can be varied bychanging the inclination of this surface 66.

Other advantages to the instant embodiment are that the linkage itselfis relatively simple and durable and is not subject to the developmentof high frictional forces as is the case with a simple sliding cam. Thisadvantage of low frictional losses is achieved by virtue of the parallellink type mounting for the block 28 in that, as a general rule,frictional losses in rotating parts are substantially lower thanfrictional losses in reciprocating parts such as slides. Theoretically,the frictional forces developed in a nonperfect journal or pivot pinsuch as in the instant device are substantially the same as thefrictional forces developed between sliding members. As a practicalmatter, substantial advantages are realized in the rotating part byreason of the fact that the lubrication problem is simplified and theadvantages of hydro dynamic lubrication are more easily achieved withrotating parts.

Changes in construction will occur to those skilled in the art andvarious apparently different modifications and embodiments may be madewithout departing from the scope of the invention. The matter set forthin the foregoing description and accompanying drawings is offered by wayof illustration only. The actual scope of the invention is intended tobe defined in the following claims when viewed in their properperspective against the prior art.

I claim:

1. A compressing tool comprising a housing, a cam in said housing, saidcam being pivotally secured to one end of a link means, said link meansbeing pivotally secured to said housing at its opposite end, means formoving said cam along an arcuate path defined by said link means, atoggle mechanism in said housing having one end pivotally mounted on afixed axis and having a knee joint in engagement with said cam, a ram,the other end of said toggle being pivotally secured to said ramWhereby, upon movement of said cam, said toggle is straightened out andsaid ram is moved.

2. A compressing tool comprising, a reciprocable actuating means, a rodpivotally secured at one end to said actuating means, a block pivotallysecured to the other end of said rod, said block being pivotally mountedon the end of link means for movement along an arcuate path uponreciprocation of said actuating means, a normally broken toggle disposedadjacent said block and extending alongside said rod and block when thelinks of said toggle are in alignment with each other, one link of saidtoggle being pivotally mounted at one end on a fixed pivotal axis, theother link of said toggle being pivotally secured to a reciprocable ram,the knee joint of said toggle having a roller thereon, said block havinga leading face which extend substantially transversely of its path ofreciprocation, said roller being in engagement with said leading facewhen said block is in its retracted position and said toggle is broken,said block having a camming surface thereon on its side which faces saidtoggle whereby, upon movement of said block from its retracted position,said roller is first pushed by said leading face and said toggle issubstantially, but not fully, straightened while said roller moves oversaid face, and upon further movement of said block, said roller isengaged by said camming surface and said toggle is fully straightened.

3. A compressing tool comprising, a block pivotally mounted on linkmeans for motion along an arcuate path, a normally broken toggledisposed adjacent to said block, said block having a leading faceextending substantially transversely of the axis of said toggle whensaid toggle is straightened, the knee joint of said toggle being inengagement with said leading face when said toggle is broken wherebyupon initial movement of said block said knee joint is pushed and saidtoggle is partially straightened, said block having acamming surfacefacing said toggle, said knee joint being engageable with said cammingsurface after said initial movement further to straighten said toggle,one end of said toggle being pivotally secured to a fixed axis, and acompressing ram pivotally secured to the other end of said togglewhereby, upon straightening of said toggle said ram is moved at adecreasing rate of speed and with an increasing force.

4. A compressing tool comprising, a housing, a reciprocable actuatingmeans in said housing, a block in said housing, a rod pivotallyconnected at one end to said block and at its other end to saidactuating means, said block lbeing pivotally mounted within said housingby means of at least one pair of parallel links whereby, uponreciprocation of said actuating means, said block is oscillated along anarcuate path, a toggle in said housing, one end of said toggle beingpivotally mounted on a fixed axis and the other end thereof beingpivotally secured to a reciprocable ram, said toggle being disposedadjacent to said block and extending alongside said block when the linksof said toggle are in alignment with each other, said block having aleading face extending substantially transversely of the axis of saidhousing and having a cam surface on its side which is adjacent to saidtoggle, the knee joint of said toggle being in engagement with saidleading face when said toggle is broken and said block is in itsretracted position whereby, upon movement of said block from itsretracted position, said knee joint is pushed by said leading facethereby to substantially, but not fully, straighten said toggle and todrive said ram a substantial distance, and said cam surface subsequentlyengages said knee joint to further straighten said toggle and to drivesaid ram a further distance with concomitant development of a highthrust.

5. Apparatus as set forth in claim 4 including a ratchet bar, a pawl onsaid block engageable with said ratchet bar, and means on said barpermitting reversal of said pawl only after movement of said blockthrough a predetermined distance.

6. Apparatus as set forth in claim 5 wherein said ratchet bar is mountedon said block and said block is movable along the axis of said bar.

7. Motion transmitting means comprising, a toggle, a block disposedadjacent to said toggle, link means pivotally secured at one end to saidblock and pivotally mounted on a fixed axis at its opposite end, saidblock having a surface in engagement with the knee joint of said toggle,and means for moving said block along an arcuate path defined by saidlink means thereby to straighten said toggle.

8. Motion transmitting means comprising a toggle, a block disposedadjacent to said toggle, parallel link mounting means for said block,means for oscillating said block along an arcuate path defined by saidparallel link mounting means, said block having a leading face andhaving a cam surface on its side adjacent said toggle, said leading facebeing in engagement with the knee joint of said toggle when said toggleis broken and said block is in its retracted position whereby, uponmovement of 7 said block along said arcuate path, said leading facefirst pushes said knee joint to substantially, but not fully, straightensaid toggle, and at an intermediate position of said block, said camsurface engages said knee joint to further straighten said toggle, saidcam surface being compensatory of the arcuate path of said block.

9. In a tool having a block movable along an arcuate path, a ratchet barmovable towards and away from said arcuate path and being axiallyimmovable, means on said block for holding said ratchet bar and movingsaid ratchet bar towards and away from said arcuate path while saidblock moves along said path, and a pawl on said block engageable withthe teeth of said ratchet bar whereby, upon initiation of movement ofsaid block along said arcuate .path in one direction, said pawl engagesthe teeth of said ratchet and prevents reverse movement of said blockuntil the last tooth of said ratchet bar is passed.

References Cited in the file of this patent UNITED STATES PATENTS925,673 Zook Tune 22, 1909 1,689,744- Neuroth -2 Oct. 30, 1928 2,052,976Harcourt Sept. 1, 1936 2,354,841 Shatf Aug. 1, 1944 2,355,520 Fischer etal. Aug. 8, 1944 2,551,916 Van Sittert et al. May 8, 1951 2,591,338Cooper Apr. 1, 1952

